1. Field of the Invention
The present invention relates to gas turbine, exhaust diffuser, and a method of modifying gas turbine plant.
2. Description of Related Art
Due to the recent high interest in environmental problems, more improved performance has been requested for thermal power generation facilities. In this situation, gas turbines have been expected to play a role of reducing CO2 because the efficiency of a gas turbine alone is relatively high and because, when combined with another power generation facility, the gas turbine can achieve a high power generation efficiency of 50% or more. An example of this is a combined cycle in which a gas turbine is combined with a steam turbine. For this reason, not only when a new gas turbine is installed, but also when an existing gas turbine is updated, it is desired that a more efficient plant will be constructed. In addition, improved performance is requested not only the main components such as compressors, combustors, and turbines but also for sections such as inlet parts and exhaust parts.
Not much literature related to technologies for updating an existing gas turbine plant has been disclosed. In addition, although some methods of reducing a loss at an exhaust part have been studied, the target is often a flow path shape or strut. In the Patent Document 1, for example, to suppress separation by a diffuser, a jet is ejected so as to trace a casing on an outer circumference side and its ejection method is adjusted. In addition, in the Patent Documents 2 and 3, the shape and position of a strut are adjusted to reduce the loss caused at the strut.    Patent Document 1: Japanese Patent Laid-open No. 2004-162715    Patent Document 2: Japanese Patent Laid-open No. 2008-157110    Patent Document 3: Japanese Patent Laid-open No. 2005-290985